If police really had all the tools available to the teams in CSI, we'd probably have far fewer criminals running around. On television, a simple zoom can show a person's face, a swipe can find full sets of prints and a bug can tell us precisely where the victim was killed. But in reality, things aren't quite so simple. Detectives even have a term for the way television has given us unrealistic expectations of our law enforcement: The CSI Effect.

But one CSI machine actually is real - although it's not helping detectives as much as it is doctors. The machine has a classically high-tech sounding name, the desorption electrospray ionization mass spectrometer, or DESI, and it was actually featured in CSI and CSI Miami as an instrument to measure fingerprints.

In reality, the machine does all sorts of things. It was developed in the lab of Graham Cooks, the co-founder of Prosolia, Inc. According the the press release:

It's about the size of a shoebox and does not change or destroy the sample that is analyzed. Cooks' students have even carried it into a grocery store and held it close to the outer surfaces of fruit and vegetables to detect pesticides and microorganisms. The team also used it to identify biomarkers for prostate cancer and to detect melamine, a potentially toxic substance that showed up in infant formulas in China in 2008 and in pet food in the U.S. in 2007. In addition, DESI can detect explosives on luggage.

Alongside the DESI, Cooks's lab is developing something called a "PaperSpray ionization" mass spectrometer. The PaperSpray machine looks like this:

The DESI and PaperSpray are quite similar, says the press release. Here's how they work:

Both the DESI and PaperSpray mass spectrometers work in a similar way. To weigh chemicals, mass spectrometers need to ionize, or give a positive or negative charge to a substance. Mass spectrometers usually do this inside the instrument under a vacuum without air. But DESI and PaperSpray can do this so-called ionization process out in the open. This allows scientists much more flexibility. DESI and PaperSpray also can do analyses without separating out all of the chemicals in a sample first (unlike conventional instruments), which provides quick results. They are also very easy to operate. "You just point and shoot," said Cooks.

So while CSI might mislead us when it comes to most of their gadgets, this one is actually pretty useful.

Contributing Editor
Rose Eveleth is a freelance writer, producer and designer based in Brooklyn, New York. Her work has appeared in Scientific American, OnEarth, Discover, New York Times, Story Collider and Radiolab. She holds degrees from the University of California, San Diego and New York University.
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